Next Article in Journal
Acute and Transgenerational Effects of Non-Steroidal Anti-Inflammatory Drugs on Daphnia magna
Previous Article in Journal
The Application of Reference Dose Prediction Model to Human Health Water Quality Criteria and Risk Assessment
Previous Article in Special Issue
Toxic and Potentially Toxic Mineral Elements of Edible Gastropods Land Snails (Mediterranean Escargot)
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:

Seasonal Variations in the Trace Elements and Mineral Profiles of the Bivalve Species, Mytilus galloprovincialis, Chamelea gallina and Donax trunculus, and Human Health Risk Assessment

Department of Chemistry, Medical University of Varna, 9002 Varna, Bulgaria
Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98168 Messina, Italy
Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, 98168 Messina, Italy
Department of Veterinary Sciences, University of Messina, Polo Universitario Annunziata, Via Palatucci 13, 98168 Messina, Italy
Authors to whom correspondence should be addressed.
Toxics 2023, 11(4), 319;
Received: 23 February 2023 / Revised: 20 March 2023 / Accepted: 27 March 2023 / Published: 28 March 2023


This study aimed to provide data on selected toxic (Cd, Pb and Ni), essential (Cr, Cu, Fe, Mn and Zn) and microelement (Na, K, Ca and Mg) concentrations in edible tissues of the Mediterranean mussel (Mytilus galloprovincialis), striped venus clam (Chamelea gallina) and the wedge clam (Donax trunculus). Samples were collected from the Black Sea (Bulgaria) four times over, a period of one year (2022). In comparison with the maximum permissible levels set by the EU and USFDA, all elemental concentration found in the bivalve species were lower than the prescribed limits. An estimation of the dietary metal intake through calculation of the target hazard quotients (THQ), hazard index (HI) and target risk (TR) was performed. The target hazard quotient (THQ) for individual metal and HI for combined metals were lower than 1, indicating no health risk for consumers due to the intake of either individual element or combined ones. The target risk value for toxic inorganic Pb and Cr was below 10−6, indicating no carcinogenic risk. According to these results, the consumption of these bivalve species is completely safe for human health.

1. Introduction

Over the past few decades, the consumption of shellfish has increased due to the potential beneficial properties [1,2,3,4,5]. Shellfish are excellent sources of proteins, fatty acids, vitamins (niacin, thiamine) and minerals (Ca, Mg, Fe, and Zn) [4]. Despite the numerous human health effects, various contaminants, such as heavy metals, could pose a risk to regular consumers [6]. All metals possess a negative impact on human health when their intake exceeds certain levels, but lead, cadmium and nickel are very toxic, even at low doses [7]. Other elements (such as Cu, Fe, Zn and Se) are essential for humans, but they may become toxic at high concentrations, as well [7,8]. This is the reason why it is of great importance to determine marine organisms’ chemical composition, regarding the content of heavy metal, in order to evaluate the possible risks to human health [8].
Among mollusks, the Mediterranean mussel (Mytilus galloprovincialis), striped venus clam (Chamelea gallina) and the wedge clam (Donax trunculus) are the most harvested and cultivated species in the world [1,2]. M. galloprovincialis is widely distributed in the coastal waters of the eastern Atlantic–Mediterranean region and is mainly farmed in the northwest coastal waters of Spain, Italy, Turkey and Bulgaria [9,10]. C. gallina is distributed throughout the entire Mediterranean, Black and Marmara Sea coasts, and is a filter-feeder, muddy sand species [1]. Black Sea C. gallina prefers greater depths of 5 to 18 m (rarely up to 25+ m) [11]. The benthic D. trunculus is an Atlantic–Mediterranean warm-temperate species distributed from Senegal to the northern Atlantic coast of France, the Mediterranean and the Black Sea, as well as along the Marmara Sea [11,12,13]. In the Bulgarian Black Sea, D. trunculus dominates the wave action upper infralittoral medium and fine sands, usually between 1 and 6.5 m (but is also observed from 0.9 to 9 m) [11].
The Black Sea is an enclosed sea isolated from the World Ocean and the large inflows of river water distinguish it from other sea basins [14]. One of the most polluted seas with higher degree of eutrophication in recent years in the world is the Black Sea [15]. The pollution of the Black Sea increases each year, which leads to a decline in fishery yield and has a serious impact on the tourist industry. The Mediterranean mussel (Mytilus galloprovincialis), striped venus clam (Chamelea gallina) and the wedge clam (Donax trunculus) are bivalve species of huge economic importance in the Black Sea region [15].
The aim of this study was to determine the seasonal dynamics of trace (Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn) and macro element (Ca, K, Mg, Na) content of three Black Sea bivalve species, Donax trunculus, Mytilus galloprovincialis and Chamelea gallina, over a period of one year, and to calculate the target hazard quotients (THQ), hazard index (HI) and target risk (TR) values for Pb and Cr as developed by the Environmental Protection Agency (EPA) in the US for the estimation of potential health risks associated with long-term exposure to chemical pollutants [16].

2. Materials and Methods

2.1. Sampling and Sample Treatment

The study was conducted four times during a one-year period (2022) on wild populations of the bivalves. The samples were collected from the area of Azalia resort zone at two points (43.24642° N 28.01972° E; 43.24781° N 28.02058° E), and from the area of Krapec to the resort St. Konstantin and Elena at four points (43.587° N 28.609° E; 43.434° N 28.37° E; 43.246° N 28.02° E; 43.247° N 28.022° E). The Donax trunculus abundance was assessed, based on bottom trawling with a beam trawl in 1–3 m isobaths, while Mytilus galloprovincialis and Chamelea gallina within 1–8 m isobaths. Only clams with undamaged valves were studied. More than 2 kg of bivalves with comparable shell lengths were collected, placed into plastic bags and brought to the laboratory. The bivalves were cleaned, rinsed with Milli-Q water, brushed, shucked and soft tissues were removed with a Teflon knife and stored in polyethylene bags at −20 °C until analysis. Around two hundred specimens of each species were taken randomly for the determination of sample mean. The physical parameters of sampled shellfish were as follows (Table 1):

2.2. Reagents and Standard Solutions

All solutions were prepared with analytical reagent grade chemicals and ultra-pure water (18 MΩ cm) generated by purified distilled water with a Millipore Milli-Q Gradient A-10 water purification system (Bedford, MA, USA). All the plastic and glassware were cleaned by soaking in 2 M HNO3 for 48 h, and rinsed five times with distilled water, and then five times with deionized water prior to use. The calibration standard solutions were freshly prepared by dilution of Optima Family Multi-Element Standard, Matrix per Volume: 2% HNO3, and Multi-Element Calibration Standard 3, Matrix per Volume: 5% HNO3 stock solution (Perkin Elmer®, Waltham, MA, USA).

2.3. Analytical Procedure

Wet digestions were performed in triplicate by weighing approximately 1.0 g of the tissues with a mixture of 8 mL HNO3 (65% Merck, Suprapur, Darmstadt, Germany) and 2 mL H2O2 (30–32% OptimaTM, for Ultra Trace Analysis, Fisher Chemical, Waltham, MA, USA) in a microwave closed-vessel digestion system MARS 6 (CEM Corporation, Matthews, NC, USA). The power system used provides continues microwave emission at each level (Table 2). After digestion the samples were diluted to 25 mL in acid-washed polyethylene bottles with Milli-Q water, and stored prior to analysis. A blank digest was performed in the same way. The concentrations of Ca, K, Mg, Na, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn in the samples were determined using ICP-OES Spectrometer (Optima 8000, Perkin Elmer, Waltham, MA, USA) with the following operating conditions: plasma gas flow—8 L/min; auxiliary gas flow—0.4 L/min; nebulizer gas flow—0.6 L/min; RF power—1500 watts; plasma view—axial/radial; nebulizer—concentric glass, MEINHARD® Type C.

2.4. Quality Assurance and Quality Control of the Method

Five sub-samples of each material were digested along with the blank sample, using the methods described above. All measurements were performed in triplicate for the samples and standard solutions. Metal contents were calculated and shown as mg/kg of wet weight. The accuracy of the procedure for the determination of trace metals in mollusks was tested using ERM-CE 278 k (mussel tissues from European Commission, joint research center, Belgium) certified reference material. The CRM was digested and analyzed in the same way as the analytical samples. The recovery values were between 86 and 103% for the individual elements.

2.5. Hazard Risk Estimation

2.5.1. Target Hazard Quotient (THQ)

The THQ, developed by USEPA [16], is used to assess the human health risk for non-carcinogenic elements in the local human population over a lifetime, in comparison with the reference oral dose (RfD) [17]. THQ was calculated as per USEPA Region III Risk Based Concentration Table [18], by using the following equation:
T H Q = ( M C · I R · 10 3 · E F · E D ) R f D · B W a · A T n
where MC is the heavy metal concentration in bivalve species (mg/kg ww), IR is the average daily consumption of shellfish (0.8 g/person/day) [19], EF is the exposure frequency (365 days/year), ED is the exposure duration (30 years or 10,950 days) for non-cancer risk as used by USEPA [18], RfD is the reference dose of individual metal (0.001 μg/g day for Cd, 0.04 μg/g day for Cu, 0.003 μg/g day for Cr, 0.009 μg/g day for Fe, 0.02 μg/g day for Ni, 0.004 mg/kg for Pb, 0.14 mg/kg for Mn and 0.3 μg/g day for Zn) [18], BWa is an average adult body weight (70 kg average) and ATn is the average exposure time for non-carcinogens [18]. Values of THQ below 1 show no harmful effect for human health.

2.5.2. Hazard Index (HI)

The hazard index from THQs is expressed as the total of the hazard quotients [20]:
H I = T H Q C d + T H Q C u + T H Q C r + T H Q F e + T H Q N i + T H Q P b + T H Q M n + T H Q Z n

2.5.3. Target Risk (TR)

Target cancer risk (TR) indicates carcinogenic risks. The model for estimating TR is shown as follows:
T R = C · C R · 10 3 C P S o · E F · E D B W a · A T c
where C is the metal concentration in the mollusk species (mg/kg ww), CR is the average daily consumption of shellfish (g/day) (0.8 g/person/day) [19], CPSo is the carcinogenic potency slope, oral (Cr = 0.5 mg/kg bw-day, Pb = 0.0085 mg/kg bw-day), ATc is the averaging time, carcinogens (day/years), and was calculated by multiplying exposure frequency in exposure duration over lifetime. The TR value for intake of Cr, Ni and Pb was calculated to indicate the carcinogenic risk, since Cd, Cu, Fe, Mn and Zn do not cause any carcinogenic hazards according to the USEPA. The acceptable values of TR are 1 × 10−6 according to the USEPA [18].

2.6. Statistical Analysis

All analyses were performed in 5 replicates and the results were expressed as the mean values ± standard deviation (SD). The mean values of trace elements were compared by a one-way ANOVA, followed by a post hoc Tukey’s test. Statistical significance was considered at p ≤ 0.05 (GraphPad Prism 5).

3. Results and Discussion

3.1. Trace Elements in Bivalve Species Tissues

Mean concentrations and standard deviations of toxic and essential elements of the three bivalve species from the region of the Black Sea Bulgaria are shown in Table 3. The summarized results of this study are expressed as means (mg/kg) of wet weight (ww).
In this study, significant differences in elemental content were recorded between different seasons (Table 3), especially between winter and summer samples. An increase in the concentration of some elements during cold months corresponds to the period of the high storage of energy reserves, before the reproduction period, as many authors reported [21,22].
Cd is a non-essential element for the human body and it is capable of producing chronic toxicity, present at minimal concentration of 1 mg/kg [22]. The concentration of Cd ranged between 0.22 mg/kg ww and 0.91 mg/kg ww for Chamelea gallina; between 0.28 mg/kg ww and 0.74 for Mytilus galloprovincialis; between 0.03 mg/kg ww and 0.09 for Donax trunculus. The maximum Cd level permitted for bivalve mollusks intended for human consumption is 1.0 mg/kg ww according to the European Community and Bulgarian Food Regulation [23]. In the literature, cadmium concentration has been reported to range from 0.204 to 0.426 mg/kg ww for C. gallina [1], 0.024 to 0.159 mg/kg ww for D. trunculus [1], 0.292 to 0.970 mg/kg ww for M. galloprovincialis [2], all sampled from the Sea of Marmara, Turkey; between 0.17 and 0.64 mg/kg ww in wild and farmed M. galloprovincialis from Boka Kotorska Bay, south east Adriatic Sea [9]; between 0.34 and 1.71 mg/kg dw in whole soft tissue of mussels collected at 14 locations along the eastern Adriatic coast, Croatia [24]. Cadmium levels in the present study were in good agreement with the reported literature data and data from international organizations.
The lead concentration of C. gallina ranged from 0.02 mg/kg ww to 0.55 mg/kg ww; between 0.07 and 0.41 mg/kg ww for M. galloprovincialis; between 0.05 and 0.17 mg/kg ww for Donax trunculus. The maximum Pb concentration for all species was found in the winter season. According to the European Commission Regulation (1881/2006/EC) [23], the maximum acceptable concentration (MAC) of Pb in bivalve mollusks is 1.5 mg/kg ww. Őzden et al. (2009) reported values of Pb up to 1.342 mg/kg ww for C. gallina [1], up to 0.916 mg/kg ww for D. trunculus [1], and between 0.292 and 0.970 mg/kg ww for M. galloprovincialis [2] from the Sea of Marmara. In their study of mussel tissues in the Eastern Black Sea, Turkey, Čevik et al. [25] found Pb levels between 5.9 and 45.9 μg/g. As a result of the Pearson correlation in the study, metal concentration in the tissues did not seem to depend on the mussel length and sampling site, according to the same authors [25]. Cohen et al. [26] reported values of 0.80 μg/g dw for the M. galloprovincialis species in three southern California coastal wetlands. Zhelyazkov et al. [6] declared the mean Pb levels of 0.251 ± 0.141 for wild M. galloprovincialis from Varna Bay, Bulgaria. The results from the current study are within the MAC and the data in the literature.
Nickel normally occurs at very low levels in the environment and seafood is one of the major exposure paths. High amounts of Ni may lead to skin allergies, chronic bronchitis, reduced lung function, and cancer of the lung and nasal sinus. The minimum concentration was found in D. trunculus (0.005–0.006 mg/kg ww), while the other two species are characterized with higher concentrations (0.003–0.51 mg/kg ww for C. gallina and 0.04–0.21 mg/kg ww for M. galloprovincialis). The maximum Ni level permitted for muscle meat of some marine fish is 0.5 mg/kg ww according to the Bulgarian Food Regulation [27]. Nickel concentration in the literature has been reported to range from 0.13 to 0.43 mg/kg ww in M. galloprovincialis from the Italian coast, West Adriatic Sea [28]; 67.8 to 1948 ng/g ww in blue mussels (M. edulis Complex) from the Baltic Sea [29]; 2194 to 6180 μg/kg dw in mussel samples from Durres and Vlora “hot spots”, Albania [30]; 0.673 to 1.618 mg/kg ww in C. gallina and 1.097 and 7.505 mg/kg ww in D. trunculus [1]. The concentrations of Ni in our study were below that reported in the literature and by various health organizations.
Cr, Cu, Fe, Mn and Zn are essential elements for humans and most of them occur naturally in many food sources. The content of Zn was different between species. The maximum Zn concentration was observed in the winter season for all species, following the order: D. trunculus (27.46 mg/kg ww) > M. galloprovincialis (21.41 mg/kg ww) > C. gallina (19.75 mg/kg ww). There was no difference among the species in the summer period. Őzden et al. (2009) concluded that the concentrations of Zn were significantly higher in D. trunculus than in C. gallina (p < 0.05) [1], similarly to other authors [4,31,32,33]. Concerning the Cu concentration of the species under analyses, it is with maximum value during the winter season (D. trunculus (26.53 ± 1.71 mg/kg); C. gallina (9.27 ± 0.05 mg/kg); M. galloprovincialis (2.72 ± 0.30 mg/kg)). These results are higher than the ones found by Őzden et al. [1,2] and are in the range determined for M. galloprovincialis by other authors [24,25,32]. The Fe levels in bivalve species ranged from 13.78 mg/kg to 120.57 mg/kg for D. trunculus. There is no maximum permitted level for Fe in bivalve species according to European legislation [23], but the US Food and Drug Administration set 80 mg/kg ww as the limit [20]. The iron concentration found in the literature was in agreement with the data from this study [1,2,9,28]. Mn values in the literature vary between 41 and 59 μg/g ww in tissues of mussels from the Eastern Black Sea [25]; 0.865 and 11.306 mg/kg ww in wild M. galloprovincialis from Bosporus of the Sea of Marmara [2]; 1.33 and 3.85 mg/kg w/w found in M. galloprovincialis at three locations in Boka Kotorska during four different seasons in 2015 [7]. There are no data regarding the maximum Mn level permitted according to the Bulgarian Food Codex [27], but the data from current study are clearly within those found in the literature.

3.2. Macro Elements

The macro elements studied were K, Na, Ca, and Mg (Table 4). Of all the elements, Na, K and Ca were the most abundant. The concentration range for these elements in the studied species was, in general, within the range reported by several authors [2,25,34]. Usually, seafood has lower contents of Na when compared to K, both in fish or bivalves from salt or fresh water [35].
Of all species, C. gallina displayed the highest levels of Mg (958.52 ± 12.17 mg/kg ww) during the autumn season, but still less than reported by Nekhoroshkov et al. [34] (1020–4320 μg/g ww for M. galloprovincialis along the South African coastline), and within the values reported by Őzden et al. [2]. The minimum concentration of this element has been found for Mytilus galloprovincialis (341.51 mg/kw).
Further, in winter, Mytilus galloprovincialis had the highest Ca, K, Mg and Na concentration. Such an increasing trend across the four seasons was not observed for the other species subject to this study.

3.3. Nutritional Contribution of the Species in Terms of Essential Elements (Benefits)

The nutritional contribution (in DRI percent) of each essential element was calculated based on Dietary Reference Intakes (DRI) [36]. The estimated daily intake (EDI) for each element was calculated using the element average concentration (mg/kg) obtained for each mollusk, considering a meal of 150 g of bivalve [35].
Conserning Ca, D. trunculus is the bivalve that can provide the highest proportion (48.8% of the DRI) of the daily required intake of this element. C. gallina can contribute to the highest percent of Mg (34.2% of the DRI), while M. galloprovincialis contributes most to the DRI of Na (38.1% of the DRI) and K (10.7% of the DRI).

3.4. Potential Health Risk Assessment

The target hazard quotients for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn hazard indexes and target risks for Cr and Pb, estimated through the consumption of the three bivalve species, are shown in Table 5.
THQ is an integrated risk index that compares the ingested amount of a contaminant with a standard reference dose [34]. The health risk assessment is done based on assumptions. The acceptable value for THQ equals to 1, according to the USEPA [18]. The elements Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn did not exceed 0.1 of THQ, and the THQ was less than 1 for all elements. Perošević et al. found that the THQFe was between 0.014 and 0.044, THQZn 0.015–0.050, THQMn 0.003–0.011, THQCu 0.007–0.019, THQNi 0.004–0.024, THQPb 0.224–0.297, THQCr 0.017–0.071 and THQCd 0.051–0.187 for mussels M. galloprovincialis from Boka Kotorska Bay, Montenegro [7], and THQs in the range of 0.3–0.7 for the elements Cr, Co, Zn, and I for wild mussels along the South African coastline [34].
The HI values, which evaluate an additive risk from different elements, were lower than 1 for each bivalve sample, which indicates that there is no concern for potential health effects.
The Environmental Protection Agency (EPA) defines TR as “the incremental probability of an individual to develop cancer over a lifetime, as a result of exposure to a potential carcinogen” [17]. The cancer slope factor (CSF) value (μg kg−1 day−1), according to USEPA, is only available for As, Pb and Cr [17]. A risk level of 1 × 10−6 has been considered the point of excess cancer risk, indicating 1 per 1,000,000 chance of getting cancer via consumption of shellfish toxic metals, estimated for 70 years [37]. The safe point for carcinogenic risks must be lower than this level [37]. The range of risks set by the EPA is 1 × 10−4 to 1 × 10−6, and it is deemed unacceptable if the risks are surpassing 1 × 10−4. A carcinogenic risk of 1 × 10−4 poses health hazards; therefore, if sufficiently large, health hazards need some sort of intervention and remediation [8]. The calculated values in this study are within the range of 10−6, suggesting that the intake of Cr and Pb by consumption of these bivalve species would not result in appreciable hazard risk of the human body. As a conclusion, the levels of Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn in mussels could be considered relatively safe for consumption according to the hazardous quotients and indexes.

4. Conclusions

The toxic, essential and macro element concentrations in Mediterranean mussel (Mytilus galloprovincialis), striped venus clam (Chamelea gallina) and the wedge clam (Donax trunculus) from Bulgarian coast of the Black Sea, at different seasons, did not exceed the European Union and US Food and Drug Administration requirements, and are within the maximum acceptable limits set by those health organizations. In terms of the THQ and HI values of the elements, the continuous consumption of these shellfish species in this area may not create health risk over a prolonged period. The target risk value for Cr and Pb was below 10−6, indicating no carcinogenic risk. Based on the results from this study, the consumption of these bivalve species is safe for human health.

Author Contributions

Conceptualization, K.P., P.L. and F.F.; Investigation, K.P., V.P. (Vincenzo Parrino), R.S., D.D. and A.M.; Writing—original draft preparation, K.P. and V.P. (Veselina Panayotova); Methodology, K.P., V.P. (Veselina Panayotova) and N.C.; Data curation, K.P., V.P. (Vincenzo Parrino), R.S., A.M. and F.F.; Supervision, F.F.; Writing—review and editing, A.M., F.F. and N.C.; Project administration, P.L. and A.M. All authors have read and agreed to the published version of the manuscript.


This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.


  1. Őzden, Ő.; Erkan, N.; Deval, M.C. Trace mineral profiles of the bivalve species Chamelia gallina and Donax trunculus. Food Chem. 2009, 113, 222–226. [Google Scholar] [CrossRef]
  2. Őzden, Ő.; Ulusoy, S.; Erkan, N. Study on the behavior of the trace metal and macro minerals in Mytillus galloproviancialis as a bioindicator species; the case of Marmara Sea, Turkey. J. Verbr. Lebensm. 2010, 5, 407–412. [Google Scholar] [CrossRef]
  3. Stanković, C.; Jović, M.; Milanov, R.; Joksimović, D. Trace elements concentrations (Zn, Cu, Pb, Cd, As and Hg) in the Mediterranean mussel (Mytilus galloprovincialis) and evaluation of mussel quality and possible human health risk from cultivated and wild sites of the southeastern Adriatic Sea, Montenegro. J. Serb. Chem. Soc. 2011, 76, 1725–1737. [Google Scholar] [CrossRef]
  4. Peycheva, K.; Panayotova, V.; Stancheva, R.; Makedonski, L.; Merdzhanova, A.; Cicero, N.; Camilleri, G.; Fazio, F. Trace elements and omega-3 fatty acids of black sea (Bulgaria) bivalve species Mytilus galloprovincialis, Chamelea gallina and Donax trunculus. Human health risk. Nat. Prod. Res. 2022, 36, 2735–2742. [Google Scholar] [CrossRef]
  5. Bat, L.; Şahin, F.; Öztekin, A.; Arici, E. Toxic Metals in Seven Commercial Fish from the Southern Black Sea: Toxic Risk Assessment of Eleven-Year Data Between 2009 and 2019. Biol. Trace Elem. Res. 2022, 200, 832–843. [Google Scholar] [CrossRef] [PubMed]
  6. Zhelyazkov, G.; Yankovska-Stefanova, T.; Mineva, E.; Stratev, D.; Vashin, I.; Dospatliev, L.; Valkova, E.; Popova, T. Risk assessment of some heavy metals in mussels (Mytilus galloprovincialis) and veined rapa whelks (Rapana venosa) for human health. Mar. Pollut. Bull. 2018, 128, 197–201. [Google Scholar] [CrossRef] [PubMed]
  7. Peroševic, A.; Joksimović, D.; Đurović, D.; Milašević, I.; Radomirović, M.; Stanković, S. Human exposure to trace elements via consumption of mussels Mytilus galloprovincialis from Boka Kotorska Bay, Montenegro. J. Trace Elem. Med. Biol. 2018, 50, 554–559. [Google Scholar] [CrossRef]
  8. Mejdoub, Z.; Zaid, Y.; Hmimid, F.; Kabine, M. Assessment of metals bioaccumulation and bioavailability in mussels Mytilus galloprovincialis exposed to outfalls pollution in coastal areas of Casablanca. J. Trace Elem. Med. Biol. 2018, 48, 30–37. [Google Scholar] [CrossRef] [PubMed]
  9. Jović, M.; Stanković, S. Human exposure to trace metals and possible public health risks via consumption of mussels Mytilus galloprovincialis from the Adriatic coastal area. Food Chem. Toxicol. 2014, 70, 241–251. [Google Scholar] [CrossRef]
  10. Eurostat. Production from Aquaculture Excluding Hatcheries and Nurseries (from 2008 Onwards). 2020. Available online: (accessed on 13 March 2023).
  11. Gumus, M.R.; Todorova, V.R.; Panayotova, M.D. Recent Observations on the Size Structure of Donax trunculus Linnaeus, 1758 and Chamelea gallina (Linnaeus, 1758) in the Bulgarian Black Sea as Status Indicators of Commercially Exploited Shellfish under the Marine Strategy Framework Directive (MSFD). Ecol. Balk 2020, 3, 63–71. [Google Scholar]
  12. Bayed, A.; Guillou, J. Contribution a l’e·tude des populations du genre Donax: La population de Donax trunculus L. (Mollusca, Bivalvia) de Mehdia (Maroc). Ann. Inst. Oceanogr. 1985, 61, 139–147. [Google Scholar]
  13. Mazé, R.A.; Laborda, A.J. Aspectos de la dinámica de población de Donax trunculus L. (Bivalvia: Donacidae) en la ría de El Barquero (Lugo, NW España). Inv. Pesq. 1988, 52, 299–312. [Google Scholar]
  14. Panayotova, V.; Merdzhanova, A.; Dobreva, D.A.; Bratoeva, K.; Makedonski, L. Nutritional composition, bioactive compounds and health-beneficial properties of Black Sea shellfish. J. IMAB 2020, 26, 3293–3297. [Google Scholar] [CrossRef]
  15. Makedonski, L.; Peycheva, K.; Stancheva, M. Determination of some heavy metal of selected black sea fish species. Food Control 2017, 72, 313–318. [Google Scholar] [CrossRef]
  16. USEPA (United States Environmental Protection Agency). Risk Assessment Guidance for Superfund I: Human Health Evaluation Manual; EPA/540/1-89/002; Office of Emergency and Remedial Response: Washington, DC, USA, 1989. Available online: (accessed on 22 October 2022).
  17. EPA. Integrated Risk Information System; U.S. Environmental Protection Agency: Washington, DC, USA, 2016. Available online: (accessed on 14 October 2016).
  18. USEPA (United States Environmental Protection Agency). Risk-Based Concentration Table. 2010. Available online: (accessed on 13 June 2022).
  19. EAFA (Executive Agency of Fisheries and Aquaculture). Annual Report for Fish and Aquaculture Consumption in Bulgarian Territory; Ministry of Agriculture and Forestry: Sofia, Bulgaria, 2012. (In Bulgarian)
  20. US FDA/CFSAN; ISSC. National Shellfish Sanitation Program. Guide for the Control of Molluscan Shellfish 2007. Guidance Documents Chapter II. Growing Areas: 04. Action Levels, Tolerances and Guidance Levels for Poisonous or Deleterious Substances in Seafood. 2007. Available online: (accessed on 31 January 2023).
  21. Rouane-Hacene, O.; Boutiba, Z.; Belhaouari, B.; Guibbolini-Sabatier, M.E.; Francour, P.; Risso-de Faverney, C. Seasonal assessment of biological indices bioaccumulation and bioavailability of heavy metals in mussels Mytilus galloprovincialis from Algerian west coast, applied to environmental monitoring. Oceanologia 2015, 57, 362–374. [Google Scholar] [CrossRef][Green Version]
  22. Sarkar, T.; Alam, M.M.; Parvin, N.; Fardous, Z.; Chowdhury, A.Z.; Hossain, S.; Haque, M.E.; Biswas, N. Assessment of heavy metals contamination and human health risk in shrimp collected from different farms and rivers at Khulna-Satkhiraregion, Bangladesh. Toxicol. Rep. 2016, 3, 346–350. [Google Scholar] [CrossRef] [PubMed][Green Version]
  23. European Commision. Commission Regulation (EC) No 1881/2006 of 19 December 2006 Setting Maximum Levels for Certain Contaminants in Foodstuff. 2006. Available online: (accessed on 15 January 2022).
  24. Kljaković-Gaspić, Z.; Herceg-Romanić, S.; Kozul, D.; Veza, J. Biomonitoring of organochlorine compounds and trace metals along the Eastern Adriatic coast (Croatia) using Mytilus galloprovincialis. Mar. Pollut. Bull. 2010, 60, 1879–1889. [Google Scholar] [CrossRef] [PubMed]
  25. Çevik, U.; Damla, N.; Kobya, A.I.; Bulut, V.N.; Duran, C.; Dalgıc, G.; Bozacı, R. Assessment of metal element concentrations in mussel (M. galloprovincialis) in Eastern Black Sea, Turkey. J. Hazard. Mater. 2008, 160, 396–401. [Google Scholar] [CrossRef]
  26. Cohen, T.; Hee, S.S.Q.; Ambrose, R.F. Trace Metals in Fish and Invertebrates of Three California Coastal Wetlands. Mar. Pollut. Bull. 2001, 42, 224–232. [Google Scholar] [CrossRef]
  27. Anonymous. Regulation of setting maximum levels of certain contaminants in foodstuff. Darjaven Vestn. 2004, 31, 2–3. (In Bulgarian) [Google Scholar]
  28. Desideri, D.; Meli, M.A.; Roselli, C. A biomonitoring study 210Po and heavy metals in marine organisms from the Adriatic Sea (Italy). J. Radioanal. Nucl. Chem. 2010, 285, 373–382. [Google Scholar] [CrossRef]
  29. Knopf, B.; Fliedner, A.; Radermacher, G.; Rüdel, H.; Paulus, M.; Pirntke, U.; Koschorreck, J. Seasonal variability in metal and metalloid burdens of mussels: Using data from the German Environmental Specimen Bank to evaluate implications for long-term mussel monitoring programs. Environ. Sci. Eur. 2020, 32, 7. [Google Scholar] [CrossRef][Green Version]
  30. Cullaj, A.; Lazo, P.; Duka, S. Heavy metals and metallonine levels in mussel samples from the Albanian sea coast, MAP/Med Pol. In Biological Effects Monitoring Programme—Achievements and Future Orientations, Proceedings of the Workshop, Alessandria, Italy, 20–21 December 2006; MAP Technical Reports Serial No. 166; UNEP/MAP: Athens, Greece, 2007; pp. 141–151. [Google Scholar]
  31. Usero, J.; Morillo, J.; Gracia, I. Heavy metal concentrations in molluscs from the Atlantic coast of southern Spain. Chemosphere 2005, 59, 1175–1181. [Google Scholar] [CrossRef]
  32. Cammilleri, G.; Galluzzo, P.; Pulvirenti, A.; Giangrosso, I.E.; Dico, G.M.L.; Montana, G.; Lampiasi, N.; Mobilia, M.A.; Lastra, A.; Vazzana, M.; et al. Toxic mineral elements in Mytilus galloprovincialis from Sicilian coasts (Southern Italy). Nat. Prod. Res. 2020, 34, 177–182. [Google Scholar] [CrossRef] [PubMed]
  33. Locatelli, C.; Fabbri, D.; Torsi, G. Heavy metal determinations in algae and clams and their possible employment for assessing the sea water quality criteria. Ann. Chim. 2001, 91, 425–434. [Google Scholar] [CrossRef] [PubMed]
  34. Nekhoroshkov, P.S.; Bezuidenhout, J.; Frontasyeva, M.V.; Zinicovscaia, I.I.; Yushin, N.S.; Vergel, K.N.; Petrik, L. Trace elements risk assessment for consumption of wild mussels along South Africa coastline. J. Food Compost. Anal. 2021, 98, 103825. [Google Scholar] [CrossRef]
  35. Afonso, C.; Lourenço, H.M.; Cardoso, C.; Bandarra, N.M.; Carvalho, M.L.; Castro, M.; Nunes, M.L. From fish chemical characterisation to the benefit-risk assessment—Part A. Food Chem. 2013, 137, 99–107. [Google Scholar] [CrossRef] [PubMed]
  36. IOM. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids; National Academic Press: Washington, DC, USA, 2005. [Google Scholar]
  37. Alidadi, H.; Tavakoly Sany, S.B.; Zarif Garaati Oftadeh, B.; Mohamad, T.; Shamszade, H.; Fakhari, M. Health risk assessments of arsenic and toxic heavy metal exposure in drinking water in northeast Iran. Environ. Health Prev. Med. 2019, 24, 59. [Google Scholar] [CrossRef] [PubMed][Green Version]
Table 1. Physical parameters of sampled shellfish (mean ± standard deviation).
Table 1. Physical parameters of sampled shellfish (mean ± standard deviation).
Striped venus clam (C. gallina)
Total weight (g)3.01 ± 0.123.15 ± 0.093.09 ± 0.023.32 ± 0.39
Soft tissue weight (g)1.42 ± 0.681.46 ± 0.221.51 ± 0.261.54 ± 0.32
Total size (cm)2.09 ± 0.342.11 ± 0.142.01 ± 0.842.31 ± 0.61
Mussel (M. galloprovincialis)
Total weight (g)3.00 ± 0.593.06 ± 0.513.60 ± 0.293.90 ± 0.69
Soft tissue weight (g)1.89 ± 0.121.76 ± 0.341.87 ± 0.051.95 ± 0.13
Total size (cm)4.41 ± 1.524.61 ± 0.315.10 ± 0.94.20 ± 1.12
Wedge clam (D. trunculus)
Total weight (g)4.02 ± 0.594.10 ± 0.494.32 ± 0.294.91 ± 0.05
Soft tissue weight (g)1.56 ± 0.121.13 ± 0.030.89 ± 0.131.26 ± 0.13
Total size (cm)2.9 ± 1.523.1 ± 0.193.3 ± 0.923.4 ± 1.11
Table 2. Microwave digestion system general and operational parameters.
Table 2. Microwave digestion system general and operational parameters.
Microwave Digestion System “MARS 6”, Acid MixtureStepInitial Power (W)Time (min)Final Power (W)Fan
T °C (max)200 °C110056001
Pressure (max)75 bar260056001
Quartz vesselsEasyPrepTM Plus360058001
Sample amount1 g4800158001
Table 3. Toxic and essential content (mg/kg ww) of the bivalve species (Black Sea, Bulgaria).
Table 3. Toxic and essential content (mg/kg ww) of the bivalve species (Black Sea, Bulgaria).
Toxic ElementsEssential Elements
Chamelea gallina
Spring0.24 ± 0.01 c0.03 ± 0.01 c0.03 ± 0.01 b8.68 ± 0.31 c0.05 ± 0.03 b1.34 ± 0.06 c30.35 ± 2.83 b0.69 ± 0.03 b
Summer0.43 ± 0.08 b0.11 ± 0.02 b0.11 ± 0.09 b13.96 ± 1.47 b0.17 ± 0.05 b1.89 ± 0.35 b53.19 ± 18.27 a1.42 ± 0.32 a
Autumn0.22 ± 0.05 c0.12 ± 0.02 b0.13 ± 0.13 b7.96 ± 3.41 c0.07 ± 0.03 b1.73 ± 0.51 b16.62 ± 5.12 c1.57 ± 0.19 a
Winter0.91 ± 0.02 a0.55 ± 0.03 a0.51 ± 0.41 a19.75 ± 0.38 a1.53 ± 0.13 a9.27 ± 0.34 a48.76 ± 5.51 a0.71 ± 0.02 b
Mytilus galloprovincialis
Spring0.28 ± 0.03 c0.07 ± 0.02 b0.04 ± 0.01 b16.00 ± 3.75 b,c0.01 ± 0.01 d0.38 ± 0.05 d13.98 ± 1.11 c0.83 ± 0.04 b
Summer0.44 ± 0.07 b0.11 ± 0.02 b0.15 ± 0.09 a,b14.21 ± 1.38 c0.17 ± 0.04 c1.92 ± 0.32 b53.91 ± 1.72 b1.44 ± 0.30 b
Autumn0.30 ± 0.03 b,c0.11 ± 0.01 a,b0.21 ± 0.10 a24.97 ± 6.03 a0.28 ± 0.06 b0.90 ± 0.17 c108.07 ± 7.33 a3.27 ± 0.75 a
Winter0.74 ± 0.06 a0.41 ± 0.13 a0.13 ± 0.03 a,b21.41 ± 1.52 a,b0.36 ± 0.05 a2.72 ± 0.30 a59.16 ± 3.54 b0.97 ± 0.01 b
Donax trunculus
Spring0.04 ± 0.01 a,bndnd10.85 ± 1.07 bnd11.34 ± 2.71 c13.92 ± 1.78 d0.68 ± 0.06 a
Summer0.04 ± 0.01 a,b0.05 ± 0.01 bnd12.47 ± 0.79 b0.11 ± 0.01 a16.01 ± 1.29 b39.78 ± 4.24 c1.98 ± 0.73 a
Autumn0.03 ± 0.02 b0.05 ± 0.03 b0.005 ± 0.008 a7.91 ± 5.18 b0.36 ± 0.43 a14.13 ± 2.88 b,c83.24 ± 1.63 b2.47 ± 1.72 a
Winter0.09 ± 0.05 a0.17 ± 0.09 a0.006 ± 0.131 a27.46 ± 2.53 a0.44 ± 0.10 a26.53 ± 1.71 a120.57 ± 13.52 a0.37 ± 0.04 b
Legend: mean values ± standard deviation; values in a column not sharing a common superscript are significantly different between seasons (p < 0.05); nd—not detected.
Table 4. Concentration (mean ± standard deviation) and nutritional contribution of 150 g serving portion for Chamelea gallina, Mytilus galloprovincialis and Donax trunculus, in terms of essential elements.
Table 4. Concentration (mean ± standard deviation) and nutritional contribution of 150 g serving portion for Chamelea gallina, Mytilus galloprovincialis and Donax trunculus, in terms of essential elements.
Chamelea gallinaMytilus galloprovincialisDonax trunculus
Ca1000–1200 *Sp786.39 ± 91.041189.81365.64 ± 30.1620517.11167.42 ± 37.1817514.6
S749.50 ± 96.751129.4588.27 ± 32.43887.4806.05 ± 37.5312110.1
A1759.14 ± 46.5226422.0385.48 ± 37.08584.81946.55 ± 37.0829224.3
W1173.00 ± 51.3117614.72282.43 ± 38.7634228.53905.96 ± 26.8258648.8
K4700 *Sp1605.20 ± 66.032415.12505.04 ± 19.543768.02559.81 ± 58.163848.2
S1527.33 ± 37.152294.91581.99 ± 52.032375.02820.50 ± 13.094239.0
A2171.43 ± 29.293266.91701.83 ± 66.072555.41171.04 ± 17.671763.7
W1891.00 ± 15.392846.03346.48 ± 19.2350210.71702.34 ± 13.022555.4
Mg310–420 **Sp573.52 ± 31.958620.5341.51 ± 10.935112.2511.67 ± 12.307718.3
S546.22 ± 36.598219.5388.29 ± 13.585813.9471.26 ± 13.777116.8
A958.52 ± 12.1714434.2426.98 ± 17.426415.2493.85 ± 12.957417.6
W452.95 ± 14.736816.2773.45 ± 21.7311627.6742.57 ± 15.1311126.5
Na1200–1500 *Sp2089.37 ± 86.0731320.91835.89 ± 7.3327518.42223.96 ± 13.0633422.2
S1988.43 ± 66.8129819.91150.27 ± 64.0917311.52112.19 ± 14.6331721.1
A3804.41 ± 16.3657138.02019.48 ± 47.2730320.22668.44 ± 29.7740026.7
W2180.00 ± 0.9632721.83813.63 ± 18.3657238.12699.63 ± 14.7640527.0
Legend: Sp—spring; S—summer; A—autumn; W—winter; DRI (in bold)—recommended daily intake values [36], used in the calculation of % DRI; EDI—estimated daily intake; * AI—adequate intake; ** RDA—recommended dietary allowances.
Table 5. Risk values (THQ, HI and TR) of each metal contaminant in bivalve species, Black Sea (Bulgaria).
Table 5. Risk values (THQ, HI and TR) of each metal contaminant in bivalve species, Black Sea (Bulgaria).
Target Hazard Quotient (THQ)Hazard
Index (HI)
Target Risk (TR)
Chamelea gallina
Spring0.00270.00020.00040.00050.00010.000020.00010.00030.0041.2 × 10−71.2 × 10−9
Summer0.00490.00070.00050.00090.00010.000090.000030.00050.0084.2 × 10−74.4 × 10−9
Autumn0.00250.00030.00050.00030.00010.000070.00010.00030.0041.8 × 10−77.7 × 10−10
Winter0.01290.00580.00260.00080.00010.000290.000180.00080.0253.7 × 10−62.3 × 10−8
Mytilus galloprovincialis
Spring0.00320.00010.00010.00020.00010.000020.00020.00060.0043.5 × 10−82.9 × 10−9
Summer0.00500.00070.00050.00090.00010.000090.000040.00050.0084.3 × 10−74.7 × 10−9
Autumn0.00350.00110.00030.00180.00030.000120.00010.00100.0086.8 × 10−77.8 × 10−10
Winter0.00840.00140.00080.00100.00010.000070.00130.00080.0148.9 × 10−71.7 × 10−8
Donax trunculus
Summer0.00050.00040.00170.00060.00016-0.00020.00050.0042.7 × 10−72.2 × 10−9
Autumn0.00030.00140.00120.00140.000200.0000030.00020.00030.0058.7 × 10−72.0 × 10−9
Winter0.00100.00170.00760.00200.000030.0000030.00060.00100.0141.1 × 10−67.4 × 10−9
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Peycheva, K.; Panayotova, V.; Stancheva, R.; Merdzhanova, A.; Dobreva, D.; Parrino, V.; Cicero, N.; Fazio, F.; Licata, P. Seasonal Variations in the Trace Elements and Mineral Profiles of the Bivalve Species, Mytilus galloprovincialis, Chamelea gallina and Donax trunculus, and Human Health Risk Assessment. Toxics 2023, 11, 319.

AMA Style

Peycheva K, Panayotova V, Stancheva R, Merdzhanova A, Dobreva D, Parrino V, Cicero N, Fazio F, Licata P. Seasonal Variations in the Trace Elements and Mineral Profiles of the Bivalve Species, Mytilus galloprovincialis, Chamelea gallina and Donax trunculus, and Human Health Risk Assessment. Toxics. 2023; 11(4):319.

Chicago/Turabian Style

Peycheva, Katya, Veselina Panayotova, Rositsa Stancheva, Albena Merdzhanova, Diana Dobreva, Vincenzo Parrino, Nicola Cicero, Francesco Fazio, and Patrizia Licata. 2023. "Seasonal Variations in the Trace Elements and Mineral Profiles of the Bivalve Species, Mytilus galloprovincialis, Chamelea gallina and Donax trunculus, and Human Health Risk Assessment" Toxics 11, no. 4: 319.

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop